瘦素对人类乳腺癌细胞MCF-7增殖及凋亡的影响

 目的 观察不同浓度瘦素对人类乳腺癌细胞MCF-7增殖及凋亡的影响，探讨瘦素在乳腺癌发生及发展中的作用。方法 采用四甲基偶氮唑蓝（MTT）比色法检测不同浓度瘦素对体外培养的MCF-7细胞生长的增殖作用，流式细胞术分析细胞周期的分布， Annexin V-FITC／PI染色法检测细胞凋亡。结果 MTT比色法结果显示：不同浓度瘦素作用24、48、72 h能够促进MCF-7细胞增殖，浓度与时间不存在交互作用（F＝0.919，P＝0.523），浓度及时间各自的主效应均差异有统计学意义（F＝12.699，P＝0.000； F＝647.881，P＝0.000）。多重比较结果显示：200　ng／ml及400　ng／ml瘦素组与对照组相比差异有统计学意义（P＝0.007；P＝0.000），不同时间段之间均差异有统计学意义（P＝0.000）。流式细胞术分析显示100、400 ng／ml瘦素作用48 h后，G0／G1期细胞比例下降14.42 %（F＝10.464，P＝0.044），S期比例分别上升7.57 %、22.19 %（F＝47.361，P＝0.005），G2／M期变化差异无统计学意义（F＝1.77，P＝0.311）。未发现瘦素对MCF-7细胞早期凋亡的抑制作用。结论 瘦素能够促进乳腺癌细胞MCF-7的增殖并改变生长周期，但不会抑制凋亡,提示瘦素可能在乳腺癌的发展中发挥促进作用。

Effect of leptin on proliferation and apoptosis of human breast cancer cell MCF-7

Objective To observe the effect of leptin on proliferation and apoptosis of breast cancer MCF-7 cell line, and to explore the effect of leptin on occurrence and development of breast cancer. Method The MCF-7 cell line was treated with different concentration of leptin in vitro. Cell proliferation was evaluated by MTT assay. Distribution of cell cycle was determined by flow cytomery, meanwhile the rates of apoptosis were estimated on the basis of Annexin V-FITC/PI apoptosis detection. Results When treated with different concentration of leptin for 24 h, 48 h and 72 h, they could significantly induce the proliferation of MCF-7 cells by MTT method. There was not interaction between concentration of leptin and time course （F=0.919, P=0.523）. The main effect of concentration of leptin and time course was statistically significant （F=12.699, P= 0.000;F=647.881, P=0.000）. Compared 200 ng/ml and 400 ng/ml with the control group, we found the difference was statistically significant by multiple comparison （P=0.007, P=0.000, respectively）. The difference was also statistically significant among time course by multiple comparison （P=0.000, respectively）.By the flow cytometry analysis, it was found that the 100 ng/ml and 400 ng/ml leptin groups could change the distributionof cell cycle of MCF-7 cell line after 48 h. Compared with control group, the cell number decreased by 14.42 % in G0/G1 phase （F=10.464, P=0.044）,but increased by 7.57 % and 22.19 % respectively in S phase （F=47.361, P=0.005）. The difference was not statistically significant in GJM phase （F=1.77, P=0.311）. However, the effect of apoptosis inhibition was not obvious. Conclusions Leptin could stimulate the proliferation of MCF-7 cell line and change the distribution of cell cycle. But leptin could not inhibit apoptosis of MCF-7 cell line. It suggested that leptin may serve as a risk factor of breast cancer development.